Za vikend nisam ništa posebnog radio.

U subotu sam išao na spoj sa curom koju sam upoznao na Tinder-u.

Išli smo u kafić, razgovarali smo o poslu, o knigama, i o interesantim mjestima u Zagrebu.

Poslije smo išli pona sladoled i pozdravili smo se.

ĆČistio sam stan, išao sam na tržnicu po hranu.

Igrao sam u video igrice.

ĆČitao sam knjigu "Just Kids" Patti Smith.

Sporo ćčitam jer je na engleskom jeziku.

Za vikend nisam ništa posebnog radio.

posebno-posebnog ( yours is correct I think, but stylistically mine fits better)

U subotu sam išao na spoj s curom koju sam upoznao na Tinder-u.

In the Croatian past verb time is made out of 2 parts: past form of verb to be + verb in its past form. You just haven't added the past form of to be.

Išli smo u kafić, razgovarali smo o poslu, o knjigama , o interesantim mjestima u Zagrebu.

Poslije smo išli po sladoled i pozdravili (smo) se.

- smo ( which is the past form of the verb to be) can be added but is not necessary for understanding ( in this case)
- the addition of ''se'' is kind of hard to explain, but in short: after and/i grammatically speaking it is viewed as a separate sentence and that sentence is missing a subject which must be there. Because of that in this context, you add ''sebe ''( or shortened version ''se'' which is preferred)--> sebe means yourself/ourselves.

ĆČistio sam stan, išao sam na tržnicu po hranu.

Common mistake, most of the Croats do not know/hear the difference between ''Č'' and ''Ć''

Igrao sam u video igrice.

Yours is completely right, but in spoken languge this form is more used

ĆČitao sam knjigu "Just Kids" Patti Smith.

Sporo ćčitam jer je na engleskom jeziku.

Again complicated Croatian sentence rules. After ''jer'' the rest of the sentence is considered a seprate sentence and that one is missing a verb, in this case to be verb