Nice, it's like the original F-Zero with the graphics of Pole Position. I like the style, but you might want to add some guardrails or a jump/hop function to alleviate the frustration of getting yourself out of the rough areas and back onto the track.
Getting stuck in the grass is meant to give a time penalty while still allowing you to shortcut over it a bit if you have enough speed. Maybe if the player comes to a halt in the grass teleport them back onto the track with a time penalty. Something to think about.
Definitely agree with what darnkittydotcom said about the delay. But even after the delay is fixed the current movement value is too small to realistically avoid anything. Also the enemy speed seems to be randomized each time, it might make more sense for it to start the slowest on level one and get predictably faster with each new level.
Good game, I really like the visual design. It pretty desperately needs some leaderboard integration though, and probably some "challenge" options to start with a higher time limit, oncoming traffic only, etc. Otherwise there's not really enough content to get players to come back, which would be a shame since this shows a lot of promise.
Derivative but fun, maybe a little too challenging or maybe that's just me?
You might want to re-evaluate your win conditions. I definitely ran into cases where my last pig had knocked out all of the gifts but I still lost the level. I think it happens when the last pig falls out of the screen before the last gift, even if the gift is in mid-air and should clearly count as a win.
I've reloaded twice now, I keep running into glitches where I get caught outside of a bubble and the next one fails to load... I can keep moving around but I can't fire at anything, none of the enemies fire at me, and if I go too far I clip out of frame entirely.
I don't know if it's just my bad luck or what, but I definitely remember running into game-ruining bugs on the previous Bubble Tanks games as well.
Very interesting game mechanic, but after you play a few round and get the hang of it there's not really much more to do. There are no levels, just a basic high score mode, not really enough content to bring me back. This idea might work really well for a puzzle game though.
@Nevitar, thanks for the advice, I have every confidence I'll get it eventually :)
All I'm saying is it's a definite balance issue - I was breezing through the game and really enjoying myself for the mostpart, but now it feels like a real grind trying to get this last achievement (but I've put in enough time that I don't want to just give up). It feels like I've put way less effort into getting the (hard) Badges on other games...
Seriously, how is anyone getting the Sky Captain achievement on this one? I can get a million points in one run easily, but can't get a run to last for more than 2 minutes at maximum... Looks like I'm stuck at 28/29 achievements, and will never get the Badge, this sucks.
 "Super Leaderboard Racing"){kind=icon}
 "HUNTER"){kind=icon}
 "Speedy Car"){kind=icon}
 "Piggy Strike"){kind=icon}
 "Bubble Tanks 3"){kind=icon}
 "Samsara"){kind=icon}
 "Reactor Mobile"){kind=icon}
 "Endless Migration"){kind=icon}
Getting stuck in the grass is meant to give a time penalty while still allowing you to shortcut over it a bit if you have enough speed. Maybe if the player comes to a halt in the grass teleport them back onto the track with a time penalty. Something to think about.