Which of these subjects do you prefer?

I like the idea of the scuba game, but sounds a bit similar to SketchVG's old "Air Escape" game, and I'm all about variety. ^_^ The water one is the most appealing to me, simply because it offers the greatest diversity in strategy applications, but the fruit concept appeals to my whimsical nature. Maybe combine the two, and make a game where your blueberry girl can squirt juice at enemies AND become a spherical juggernaut of doom!

Then again, the scuba game could easily involve inflatable pirates, which is a huge incentive...

Whichever one you wind up finishing, I offer you my heartfelt kudos for even attempting such an undertaking!

If you have trouble with that sort of thing, let me know. I have loads of experience in flashing out thematic settings. There are a TON of underwater-themed opponents and obstacles! Various aquatic life (such as sharks, urchin, eels, dolphins, whales, sea-weed, seahorses, lion fish, puffer fish, octopi, etc...), mermaids/mermen, other divers, sea monsters, pirate ghosts/skeletons/zombies, various forms of sharp trash... All sorts of baddies! And of course, you can always re-use the same sprites with color varations, and voila! Your single grey "generic diver" enemy is suddenly also a blue "speargun diver" a red "grenade-throwing diver," a yellow "speed diver," or the dreaded black "airgun diver."

It all really comes down to how much effort and time you want to spend on it, I suppose, but the posibilities are limitiless!

This next bit is all brainstorming and workshopping critique and suggestion. Feel free to take any of these ideas and run with them, or ignore them completely.

Scuba Game - I agree with your sentiment to make this one center around underwater play, though having one or two areas of out-of-water and drysuit bouncing could prove to be a fun change-up for a midgame tedium breaker. Have her find her way into a submarine or air-filled cave during her underwater adventures, and you wouldn't even risk a theme break!

And might I suggest the idea of ballast "power-ups?" If you have her inflate to rise, and deflate to sink, ballast could add or remove weight from her in order to make her respond to either sinking or floating in a faster fashon. Also, the more ballast she has, the bigger she can get without rocketing towards the surface, which might make for interesting design elements. Why would less ballast be good? well, maybe there's a point where needing to go really high up while staying small could be beneficial or necessary?

Another thing that you might want to think about is that the character has no way of affecting her environment at this point (other than bouncing on crabs' heads, which will become irrelevant if you minimize the out-of-water mechanics). If you're going for a pure dodging game, that's all well and good, but otherwise I reccommend giving her some sort of offensive capibility. A spear gun or diving knife would easily fit the genre, and with range or ammo limitations, would be easy keep the player from overusing. Another consideration would be a compressed air gun, which could be used for both offense (inflating enemies until they pop/float away) OR puzzle solving (inflating waterlogged barrels to get them to float out of your way and such, or using it as an impromptu propulsion system)

Water Game - Your key mechanic looks pretty solid, I'm just curious how it'll look and work in a more interactive environment.

Blueberry Game - I didn't really understand what was going on here. When she turns into a blueberry, she becomes floaty? I'm with Inflate123 on this one; using the blueberry game mechanics for the space game makes a lit more sense. For a blueberry game, you might look at games like "Sonic the hedgehog" and "pinball madness" as models for inspiration. Center the puzzles around velocity, weight, and mass, rather than jumping and floating.

What do I mean? Well, velocity could come into play rather easily if you have a huge blueberry girl rolling down a hill, she's going to flatten anything in her path (anything that doesn't pop her, that is), and likely make quite a dent in whatever stops her. Weight is easy to figure out; If you have a pressure plate that needs to have a metric ton of pressure on it to open a door, a deflated blueberry girl can jump up and down on it all she likes, and still won't have much effect, but a juice-filled berrygirl might have a chance. Mass is a little harder to imagine (from my perspective), but it could be important for object displacement (expanding beneath a platform to force it to raise) or omnidirectional switches (having to press a button above, below, and to either side at the same time). Bouncing really seems a minor element to me in a blueberry-themed game, and while it could certainly be a crucial component, it pales in comparison to the other avenues you could take the game down.

Again, cheers to you for this epic undertaking! I hope things come together for you, and we see one or two of these fully realized!

Most commercial apps and games stopped supporting Win 98 a very long time ago. (I think World of Warcraft supported it unofficially until about three years ago, but that was one of the last ones I heard about.) Since XP itself is about seven years old, you're safe.

Just make your game. For the handful of people who can't play it for some technical reason (what about Mac users?), there's always YouTube, where they can see it even if they can't play it.