Is it possible to clear Hex Defense levels in "hard" mode?

The main key to hexdefense (in easy or hard mode) is upgrading towers - I don't usually do hard mode but I saw your question and tried Pinball in hard mode to try it out... I got past wave 20 with only 4 towers by upgrading: The strategy I used was to put lazers in a way to maximize damage where creeps go and to use missles (red) to take remaining hits.

• I first put a lazer just above the eastern + to catch creeps on their way up (it is helpful to first note their pattern without any towers).
• Then I put a missle as soon as I could N, N, NW of the exit to take care of 1 or 2 stragglers on wave 2.
• Then I upgraded both of these fully.
• Then I put a missle SE, SE, NE of western + to maximize the lazer's damage.
• After upgrading that, I put a second lazer S, SE, SE of the western + to double the lazer damage on the diagonal between the two lazers and upgraded (both these upgraded lazers were able to take out the fire boss on wave 15).
• Then I put a few more missles in, not impeding creeps current path.

This got me to wave 24 (which is very horrible since I know people have done FARRRR better - leaderboard shows wave 117, prolly on easy mode), but this is just one strategy to work with, though I still don't know how people get to wave 260 on the Intestines level, or even to wave 50.

I've finished all levels in hard mode without losing a single "life". Clearly, aim is to put as few towers as possible. At wave 20, my configuration is often (always ?) :

• 2 (rarely 3) laser or wave towers (or combination), depending on the field
• 3 or more rocket towers
• I never use gun towers unless not upgraded to block a passage
• all towers always full upgrade (Except gun one)

Now here is how I display towers :

• Laser towers have to be able to shoot for incoming and outgoing creep (meaning on an angle) They have to shoot on at least 4 blocks in a line for both incoming and outgoing.
• Wave tower have to be placed to hit on at least 6 blocks when they are full upgrade (else they are no use compared to there price), I don't use them on all maps
• Rocket towers have very high range, place them to be able to shoot the whole map, but also to block some passages
• Look the way creep go without towers a place towers wisely to modify this route. I usually manage to make them take a precise route with very few towers
• When you count the number of blocks a laser or wave tower shoots, count slow blocks as 2 and speed blocks as 1/2.
• I usually start with a level 2 laser tower. This single tower destroys on its own the first 3 waves (or maybe not totally for the third one). But care to place a rocket tower before wave 5 and green boss.
• Concentrate on upgrading towers before placing new ones (unless new one is absolutely needed to block passage a make other ones shoot better.

I currently use a similar strategy to dalshim and have managed to complete 19 of the 20 levels on hard mode, level 3 'islands' being my downfall. As far as I can tell, the trick is to force the creeps into a pathway of four or more straight blocks to maximize damage, then use the rockets to do the rest. On the levels which have little or no options to do this, just force a path with mini guns around the rockets to increase the time they have to do damage, and as said, upgrade early rather than buy more where possible.

Any advice specifically for islands level would be appreciated as this method does not seem to work! And all videos online are for easy mode