The "slow" effect is a joke against high tier mobs (particulary the last blue ones), you sould change the name of the type of game "survivor" to "desperate defense" or sumthing like, cuz noone can get to the end of it.
Other then that, it is a cool, adictive game 3.5-4 of 5.
I prefer to get money first, so i put up to 60 in money, i save 9000 for that smg and next i save 40000 for that assault rifle, but other options may be better. After i get the rifle, i take every point i put in money and spend them in exp first, to get up to 60 again, then in running 30, damage 30, crit chance, crit damage, armor 10 each, 30 life, then i put 60 in running and so on.
lol, finished last mission with human using only corvettes, assault and bomber corvettes fully upgraded, not very easy but certanly one hell of a fight.
I beat easy the thunder with lev 4 damage, fire rate and flag and lev 3 flag, my boat was only lev 4, if it was lev5 i would have taken either lev 3 damage or lev 2 flag