For what it is, this game is brilliant.
The only real thing I can criticize is the way you sometimes get stuck on spawning enemies when you enter the shop at high speed.
Everything else is great!
Strategy/stat priority:
Defense is you most important stat, but works most efficient with the other on appropriate levels, as follows. After getting all stats to Level 4 rank 9.
Critical strike to 100%
Attack damage so all enemies get 1 hit.
Defense with everything else.
Speed levels as you levelup, you level up faster if you follow the above recipe.
The reason you have to 1hit enemies is that enemies hit back every time you hit them. In other words you need 2x the defense if you have to attack them twice instead of once. This makes 1hitting and putting everything else in defense the most efficient use of your skill points.
It is easy to see when you hit the point where you need more attack. Suddenly you start taking huge amounts of damage, double damage.
Great job VaragtP!