For 20k Survival:
Become Level 35, where you can equip the laser and drop the rocketlauncher; activate endless jumps, double damage and bonus health; during the stage, keep pressing jump to avoid all obsticles and most enemies, only dropping down to collect powerups, most importantly the rocket launcher. The rockets will do the rest
the combined gems are too weak!
for example: combining 3 lvl 5 health gems with the values: 21, 12 and 15 results in a level 6 gem with a value of 21. Wow, what an increase! 0.0
apart from that, i think the game is not very well balanced. sometimes I lose a fight, the next time I get 3 Stars on the very same fight without any changes on my side. And most of the time the minions just 1shot each other...
I dislike, that your opponents strength depends on your own performance. I had a quite perfect run, got second place. On another try, i trolled around the first meters, getting last, and then drove normally and tadaaa, i was like 3 seconds slower than the other run but finished first..
do the levels get harder over time? when i did the first level for the first time, i did lose mby 1/3 of my hp; now i did the same first level for the 3rd time; this time I lost my henchman and died twice myself, even though i got 2 damage reducing items? 0.0