I'd be hard pressed to describe the other episodes as "innovative". Though we do have episode 3 files and what they threw around conceptually is interesting.
There's the Weaponizer, a weapon that could absorb liquids, metals or concrete to shoot different things(like water). There's some hints that the "charge gun" seen in the ravenholm episode came from episode 3 as well.though potentially scrapped early on
There was also a flamethrower and an ice gun. There was also a "Teleport Gun".
Additionally there was a weapon called "proto1", which doesn't seem fit for use considering the name but is unique; it absorbed props to gain ammo, could emit a wave to see enemies through walls and could shoot through thin walls.
In terms of enemies there were the "Margarita Soldiers", enhanced combine that other combine could scavenge their enhancement from and then use it themselves.
They had three different variants(mid, big and fast) and snarled for some reason, so probably something relevant there. Their enhancements were Shields, Propellers, Miniguns, Saws, RPG, Mortar, Bomb, Dartgun and Brain.
One of those is apparently super speed, flight has also been mentioned but that is obvious. However based on some code, it appears the player was meant to use some like Bomb; there is also a "factory" for these things.
There is also code for a companion to carry these and thats probably how. The advisors you can see in that particular piece on concept art in the OP might be "Roaming Advisors", an edited gunship that could cause avalanches and make shields.
And finally there's Surface/Blob, an entity used to showcase the blobulator system; which has 5 sizes(since they can split and merge) and 4 variants, it'd chase the player wherever(being a blob that could reform and climb)
They had repellers, nests to regenerate. An interesting piece of trivia is that the older version of it tries to call the hydra model; and its later code refers to tentacles.
>>131830
> this is just a taste of what the original HL2 was going to be before the beta was leaked
This is a common piece of misinfo but no, the actual leaked beta is very close to the final in tone; the famous 2001-2002 era was solely leftover files.
Ravenholm is however one of the earliest to hit its final state yes; its tone was set way before anything else.