My first owned computer. I got it sometime in nineties, from neigbour, one year before my first PC. It was painful to work on it, especially without any permanent storage. Later I managed to connect IQ 151 with tape recorder (not casette, but the magnetic tape rolling from one reel to another), so I didn't have to write my programs on paper :) One of the first things with my new-old heating machine was cuting of the speaker-wire and putting the on-off switch to it. The sound of every key pressed was just horrible, making the use of machine in the night impossible! Very high squeeky sound after every key pressed.
In the end, I had made some games in basic, recorded on the tape. Snake and some sort of RPG made by characters. The biggest thing I did was probably a DOS-like system - it was able to create and edit text files in memory, had commands like MEM, DIR, CD, etc. In the winter, it was beautiful to sit by the computer, because the heat coming from the massive piece of metal in the back, serving as cooler, was warming the room by few degrees. I have beautiful memories on this orange thing. In fact it helped me a lot with starting to think as a programer.
I remember, that there was special sort of machine-code input, activated by key press when starting up the system.
I had also more cartridges, but they were probably defective, so I managed to use only Basic.