I tried to jump using the space bar. However, it gave no indication of a jump, nor did it succeed in moving over the fence. What I found does work, but only sometimes, if by "looking" up at the sky, it will sometimes "climb" over the fence.
Likewise, I had to look at an upward angle to "lift" the selected item high enough to place it on/in a workshop (anvil, sawmill, smelter, cauldron).
To get a potion, I had take a step or two back and then look lower to "dip" the vial in it, which is difficult to aim because I have to halfway look at he sky to lift the item high enough to place it in the cauldron, and then _hope_ I aimed well enough to go in.
The sawmill took awhile to figure that the "0.2 <= (number) <= 0.7" meant the sawmill will only cut logs with those min/max sizes. It is also very difficult to cut the logs within those size limits due to the design of the UI. Perhaps some tick marks could be added to indicate about were to cut.
The anvil also took awhile to figure out: I needed _all_ the parts on the anvil, then hit the anvil once to combine and craft them. At the very least, give an indication that more resources are needed (it does not need to say which, only that something is missing).
The smelter was the first and easiest to figure out: I was going to try clicking on it while holding a "gem" (how a gem becomes an iron ingot is beyond me), but as soon as I was close enough to click, it also happened to be the input region and automatically took the gem and produced an ingot.
Another issue is with drinking potions: I have to click and hold the right mouse button for several seconds until it finally "drinks".
My suggestion would be that when "holding" an item, it appears the same way and place a tool would appear when equipped. Then, use/place/drop the item by clicking while the targeting dot indicates what/where to use/place/drop it. Simply clicking on the basket (box) could put the item inside it. Clicking the anvil could add the item on top. Clicking the sawmill/smelter/cauldron could do the logical thing while holding the correct item.
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One final note: While writing this, I closed and restarted the game to get those "0.2" and "0.7" numbers. This time, the space key worked to jump and I did not have to look as high in to the sky to 'lift" an item off the ground. But I did find another issue: When I grabbed a cut down tree, the game suddenly made the tree disappear entirely and made me "run" backwards at "Warp Factor 10" -- so fast it sent me off the edge to drown and die in the water before I could react.