The different speed factors in this game:

• always move up (except auto-scroll level)
• get the speed power up (blue roll)
• avoid as much lag as possible
• kill the boss fast (smash fast)
• get the lowest score

from those factors, different strat can be built

Low Score/Ratio

At the end of each level, the game countdown all the points earn. From what I've calculate, the time for the score to go zero (countdown time) would be ratio * 0.017, or score / 200 * 0.017. For example, with a score = 4600, the ratio = 23% and the countdown time will be 0.391 seconds

There are 2 requirements for lowering the ratio:

• kill less enemies, but at least 1, sometimes it's better to kill enemies for safety for instance in autoscrolls or to get specific items
• waste a lot of shuriken, better when they are shot close to walls/decorations to have a good dps and less lags. Smashing during the run can be painful ahah

Minimal lags

The game tend to lag easily and simply because there is too much things happening on the screen. For most speedrun strat we don't kill the enemies on the way and we have many of them displayed on the screen. Lucky enough the game stop spawing those enemies after a number, except for some specific ones (e.g. hidden in rock). The game would then starts to lag when those enemies shoot things at us, it's better to outrun them as soon as possible.

The red scroll power up (big shuriken) makes more lags than the regular shurikens. Also laggy when the shuriken stays long on the screen, it's better to make it disapear quicky like shooting at the last moment or shoot at walls/decorations, but it depends on the level and on how many enemies spawn

The biggest lagging would happen when the boss spawn, all the enemies behind are catching up, appear on the screen again and start shooting. Some enemies with more complex animation would create more lags (e.g. dogs), it might be worst to kill some enemies before the boss

Safe Strat

or "I want to finish the game at least one time". Casually the game is not easy because of not having a life bar and so many enemies on the screen. Regardless the strat you will need the blue scroll to go faster. Dying once would mean loosing the speed power up and makes the game difficult again. The score and lag doesn't matter much here and it's suggested to grab the shuriken upgrade (red scroll). Overall

• get the blue scroll and red scroll on the first level
• outrun the enemies on screen to have the safe way to the boss
• when reaching the top of the level, before the boss spawn, shoot down to kill all the enemies following you, they won't respawn at this point

Fastest Strat

This is where you will smash very hard to lower the score/ratio as much as possible and to kill the bosses very quickly. The challenge here is to figure out when it's better to reduce lag vs reduce the score.