Short but Awesome!
Nice work!
Unique upgrades for each character, 4 choices of sub weapons for different situations(although 2 & 4 seems to come in handy the most) and epic boss fights!
I love fighting bosses where each of their parts can be destroyed separately, to kinda handicap it for a moment!
The only thing was that it was way to short for the last tier of skills(requires lvl 10 to learn) to really have any effect (unless you save up all/ of your skill points and pump everything into it once you hit lvl 10, but is really suicidal unless you are really pro or playing on easy mode). And maybe add a pause button.
Its also a bit weird that a game with 3 characters to choose from has only 2 save slots. Anyways thats not really an issue..
Btw where's Terra Guardian 1?? Is this a sequel? Make another :)
Oh and 1 more thing, shouldn't veterans rely more on skill than luck? xD