Hi, Guys SmileBC Here! Just Kidding. But seriously how's life. Alright, let's get down to business. What I suggest is simple: When you take knockback (say for example you get hit by a troll) and you hit a wall that's behind you while flying through the air, you would take damage. Because well, if you hit a wall behind you in real life I'd imagine it would hurt A LOT.
So to address the question of will the block matter: Yes yes it will. In fact, I've come up with a system to use for this. In this system, there are 3 different densities of block (Names are not final leave comments for what they should be) and they are: Soft, Compact, and Hard. Soft would be blocks such as Leaves, Dirt, Snow, etc. you wouldn't take very much damage maybe 3-5 (all health losses are up for debate.) Compact would be harder blocks such as Gravel, Sandstone, Wood, Mossy Brick (moss cushions the impact) and you'd take 6-7 damage. (again leave suggestions.) Hard would be mostly stone: Stone, All Bricks (except mossy,) Also when I say all stone, ores, and gems are included. you would take 8-10 damage.
Now on Snow: Snow when you hit it would leave a chilling effect on you so you get slowness, perhaps your screen looks like it does when you take freezing damage in Forodwaith.
Effects after Impact: Decreased Visibility. When you get impacted like this, often you will feel decreased visibility for a time because the back of your head would be hit. Therefore you would have decreased visibility for several seconds. Nausea? maybe because you wouldn't feel good I dunno. Slowness. Your legs and would hurt after hitting a wall. Weakness. Same as Slowness
When you hit certain blocks they could show signs of damage from you hitting it if you hit the wall hard enough. Disclaimer: I dunno how realistic this part of the suggestion is but I'm putting it anyway. When you hit 1-2 blocks layers of any soft block you could actually break them. And if the wall has dirt on the outside but stone right behind then you'd cut through the block leaving the stone. It could make Stone bricks cracked and cracked stone bricks broken. (Is this too extreme? Should I remove this part?)
The other option for this would be you could leave an imprint in the wall for a few seconds after hitting it. This would mostly be for Soft Blocks
Well, that pretty much concludes it cause there isn't really much more here to discuss!
As always Constructive Comments and Criticism are always welcome! (leave comments to improve suggestion)
Signing Off Now - Arcen