The jogging animation looks really goofy, like the character is speed-walking. This isn't necessarily a huge deal, but it was one of the first things I noticed.
Animation isn't my forte, but for now I've slowed down the speed of it so it doesn't look so much like the legs are struggling to move fast enough.
-Horizontal movement is slow while jumping height is extreme. It just didn't feel balanced.
Jake Birkett said something similar, so now I've increased the maximum horizontal speed by 20% (much more than that and I found it uncontrollable), increased the rate of acceleration, and given it more gravity and initial speed when jumping (so it still jumps the same height, but should take less time to do it.)
-The balloon image that comes up when you complete a level really shouldn't be so blurry.
Fixed. All the balloons are blurry at the edges to stop them looking pixelated, but the menu ones being so much bigger than the in-game ones really needed a different blur-factor.
-In level 3, I went to stomp on a balloon and ended up on the second floor with no quick way to get back as I watched a huge group of balloons on the lower level go by. This is one of the reasons I don't like "Up" as the jump button in games. If it was another key, then you could easily use Down+Jump to drop back down and avoid these sorts of issues.
That could still just use the down key - it's just not something I'd really thought about. But I guess it would open up more possibilities for future level design too, so I'll look into it, it might not be that hard to add.
-I'm not a fan of games where holding Jump makes the character bounce. Of course, I was releasing the key early most of the time, but it's still pretty easy to accidentally jump a second time and screw up everything by hitting balloons you didn't want to.
OK, I've altered it so that you don't keep jumping on platforms without releasing the jump key. Thinking about how the controls in Bubble Bobble worked, when bouncing on bubbles, I decided to keep it so that you still bounced on balloons by holding the jump key though.
-I really didn't like that lives carried over between levels. Having to deal with multi-part balloons flying all over the place in level 2, I went into level 3 missing a ton of lives.
That's the idea of arcade mode - there was also meant to be a casual mode, in which you just play one level at a time trying to complete it without loss of lives or in a short enough time, but it isn't finished yet - I'm not sure whether I'll finish it in time for the next update.
-I feel like the game could benefit from an attack button, or at the very least the ability to rush straight downward if I press Down while in the air. That would help with aiming and make the character feel more powerful and able to deal with things.
...
In the end, I think the primary issue for me was just that it's a pain to deal with the balloons. If the character moves too slowly, jumps too high, falls too slowly, is able to bounce off of balloons rather than crushing them and doesn't have the strength to pop a balloon against a wall, then it just doesn't feel good to me. That said, since all the major issues are control-related, I think it could be drastically improved with some simple adjustments.
With the adjustments made to the character, not only does it move faster, but it has more mass and acceleration (so more force I guess) in move horizontal and vertical directions, and even without a downwards attack, it's certainly easier to destroy balloons against walls and probably against the floor too.
I also want to make changes to a lot of the level designs, so give me a day or two, I'll try to remember to post here when the updated version is out, then let us know what you think. (I'll also see whether I can fix marcgfx's problem with it, based on my guess that it's being caused by some platform shaders taking 4 texture coords.)