In addition to the above, 「さっ」 and any other character or word followed by 「っ」 indicate that the sound is abruptly cut off. For example: 「えっ？」/What!?

It depends on the syllable that comes after it not before. The sound of any syllable with a '' ﾂ '' after it in a word doesn´t change, but, the sound of the first letter of the syllable after it is maintained for the same period of that of a single syllable. So for example in サッカー　(sakkaa) you pronounce the sound of the first letter of the syllable after the small "tsu" maintained over 2x the time of a single syllable (sak-kaa). It may sound as if you paused on the "k". By the way, it doesn´t matter wether it is katakana or hiragana, if it has a small "tsu" the same thing apply to both.